Refrigerating apparatus



Feb. 11,1941.

A. o. GROOMS REFRIGERATING APPARATUS Filed April 16, 1938 4 Sheets-Sheet 1 llfl loz ENTOR.

BY ATTORNEYS Feb. 11, 1941. 2 A. o. GROOMS REFRIGERATING APPARATUS Filed April 16, 1938 4 Sheets-Sheet 2 I'M M: I a ,a 0 u u I 8 8 6 w w 1/, .m 1 4. m

INVENTOR.

ATTORNEYS BY A%Ww Feb. 11, 1941. A. 0. always 2,231,532

REFRIGERATING APPARATUS Filed April 16, .1938 4 Sheets-Sheet 4 CQLDER WARMER L COLDER. WARMER ATTORNEYS Patented Feb. 11, 1941 UNITED STATES PATENT OFFICE REFRIGERATING APPARATUS poration of Delaware Application April 16, 1938, Serial No. 202,515

10 Claims.

This invention relates to refrigerating appara tus and more particularlyto refrigerator control.

In refrigerator controls it has been deemed necessary to satisfy the demands of the public to provide a control in which a considerable range of temperature adjustment isprovided together with a single cycle automatically reset defrosting device, as well as a convenient device for shuttin off the refrigerator. To provide a control which incorporates all these features has required a rather complicated and expensive structure.

It is an object of my invention to so improve the structure of refrigerator controls that all these functions may be accomplished in a very simple control.

It is a further object of my invention to make it possible to provide satisfactory defrosting by a single cycle defrosting means in any position of the temperature regulator.

Recently it has been customary to place refrigerator controls directly within the food storage compartment of refrigerators. I find that under such conditions the parts of the control tend to corrode, especially where high humidity prevails.

It is a further object of my invention to prevent this corrosion, and particularly to provide a carbon resistance heater in parallel electric circuit relationship with the switch contacts so that a small supply of heat is always available for preventing this corrosion.

Heretofore single cycle automatic reset defrosting devices have been in the form of a single cycle loading device which loads the temperature responsive means or bellows for a single cycle. This necessitates considerable additional mechanism and it is an object of my invention to simplify the refrigerator control by eliminating this single cycle loading mechanism in a control providing automatic reset defrosting.

It is another object of my invention to provide a single cycle automatic reset defrosting device for a refrigerator control in which the stop means for the snap acting toggle switch device is changed so as to provide a higher switch closing temperature for defrosting purposes.

It is another object of my invention to provide a refrigerator control in which a single knob controls the temperature regulation, the automatic reset defrosting device, and the manual shut-off.

Further objects and advantages of the present invention will be apparent from the following description, reference being bad to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. l is a vertical sectional view through the refrigerator control embodying my invention;

Fig. 2 is a sectional view taken along the lines 2-2 of Fig. 1;

Fig. 3 is a sectional view taken along the lines 3-3 of Fig. 1;

Fig. 4 is a. sectional view taken along the lines 4-4 of Fig. 1;

Fig, 5 is a diagrammatic view showing the bottom of the refrigerator control connected to a refrigerating system;

Fig. 6 is a front view partly in section showing the control in single cycle defrosting position;

Fig. 7 is a rear view of the refrigerator control showing the switch in off position;

Fig. 8 is a fragmentary front view of a modified form of control shown in defrosting position with the temperature regulating knob in the warmest position;

Fig. 9 is a' view of the temperature regulating knob and its dial plate with the knob shown in warmest position;

Fig. 10 is a view similar to Fig. 8 in which the temperature regulating knob is in its coldest position; and

Fig. 11 is a view of the temperature regulating knob in its coldest position together with its dial plate.

Briefly, I have shown a refrigerator control having a bellows and a cycling snap acting switch mechanism in which the switch-lever is provided with a normal stop in the form of a leaf spring which determines the normal differential of the switch and a second stop in the form of a screw which controls the cut-in point for the single cycle when the normal stop is rendered ineffective to produce a single defrosting cycle. In one form the defrosting cycle is kept at a constant upper temperature limit by a compensating device operated by the temperature regulating mechanism. A carbon type heater of a fraction of a watt rating is connected in parallel electric circuit relation withthe switch contacts for heating the interior of the switch casing to preventcorrosion of the switch parts.

Referring now more particularly to the drawings there is shown a frame member 20 formed of a single piece of heavy metal which is bent so as to form a frame extending over substantially all of the bottom 22 of the switch as well as the major portion of the side 24, the top 2'6 and one end 28 of the switch. The operating bellows 30 rests upon the bottom portion 22 of the frame member 20 and has a threaded neck 32 extending through the aperture in the base portion 22 and fastened by a thin nut 34. A small tube 36 extends from the neck and is connected to a thermostat bulb 38 which is mounted in heat exchange relationship with the'evaporating means 40 as is shown in Fig. 5.

The evaporating means 40 as well as the refrigerator control is mounted within the food compartment 42 of a. domestic refrigerator as indicated diagrammatically in Fig. 5. The evaporating means is a part of the refrigerating system which includes a compressor 44 driven by an electric motor 46 for withdrawing evaporated refrigerant from the evaporating means 48, and forwarding the compressed refrigerant to a condenser 48 where the compressed refrigerant is liquefied and collected in a receiver 68. From the receiver 68 the liquid refrigerant is forwarded through a supply conduit 62 under the control of an expansion device 64 to the evaporating means 48.

The bellows 88 is provided with a conical pointed tip which engages a pressed metal bellows follower lever 56 pivoted upon the pivot pin 68 which extends through the ears 68 formed from the end portion 28 of the frame member 28. The bellows follower lever 66, at the end opposite the pivot pin 68, has a pair of bent down portions 82 provided with notches which receive a flat secondary toggle lever 64, which has a general U- shape and has knife edges upon the legs of the U-shaped portion which engage the notches provided in the portion 82 of the bellows follower lever 66. The portion of the U-shaped lever 84 which connects the, legs of the U-shape is hooked by a tension type coil toggle spring 88 which has its other end hooked around an upwardly extending post 68 of the contact lever I8. This contact lever 18 is pivoted upon-a pivot pin 12' and held in place by a spring clip 14 which engages grooves in the pivot pin I2. The contact lever I8 is also provided with a notch I8 which serves as a stop for the secondary lever 64, and aids in providing satisfactory contact pressure for holding the contacts in closed position until tripping time.

The bottom of the contact lever 18 has riveted to it a thin sheet of insulating material I8 which bears upon the rivet head of the movable contact 88. This movable contact 88 is fastened to the free end of a very thin U-shaped strip 82 of spring bronze, beryllium copper or similar material. The other end of this U-shaped strip is fastened in place by a rivet mounted upon the top of a metal post 86. This metal post 86 is lodged within an insulating member 88 which is fastened to the bottom portion 22 of the frame member 28 by screws 88. This insulating member 88 has portions which extend upwardly through the aperture in the bottom portion 22 which include a portion surrounding the post 86 and a. second portion 82 which receives a carbon heater 84 as well as a binding post 88.

The post 86 is connected by a. screw 81 to the conductor I82 which connects to the power line while the binding post 86 is connected by a screw 81 to the connector I84 connecting it to the other power line I88. The carbon heater 84 is connected by the conductor I88 to the fastening screw 8'! on the post 86 and connected by a shorter conductor to the fastening screw 81 on the binding post 86. A conductor H8 connects to the post which supports the stationary switch contact 84 with the electric motor 46. The conductor H8 is fastened to the stationary contact post by a fastening screw 86. By this arrangement the opening and closing of the switch contacts 88 and 84 stops and starts the electric motor 46 while at all times a small amount of electric current flows through the carbon heater 84 and thereby protects the switch mechanism from corrosion.

The bellows 88, which is filled with a volatile fluid, is opposed by a tension type coil spring H4 hooked at its upper end to a projecting portion of the bellows follower lever 56 and hooked at its lower end to a U-shaped member H8, which is threaded upon the adjusting screw-H8. The U-shaped member H8 is provided with a pair of tongues I28 which engage a vertical slot I22 formed in the rear portion 24 of the frame member 28.. This tongue and slot construction securely guides the U-shaped member H6 and prevents its rotation when the adjusting screw H8 is turned. The upper end of the adjusting screw H8 extends through a sleeve I24 which is threaded into a molded control knob I26 and into a bushing I28 for fastening the knob to the bushing. The bushing I28 is rotatably mounted upon the shank of the adjusting screw H8.

The upper end of the adjusting screw H8 is provided with flats upon two sides and receives a serrated washer I88 held in engagement with the upper end of the adjusting screw H8 by a fastening screw I82. This serrated washer I88 slides within the splined recess I84 which is provided within the molded knob I28 and which is concealed by a metal cover I88. Thus the knob I28 is slidablev axially upon the screw H8 but rotates with it by reason of the spline construction. The bushing I28 is grooved toreceive a leaf spring member I88 which at one end is fastened, by the screw I 48, to the top portion 28 of the frame member 28. At the other end this spring member is provided with a turned down lip I44 which is adapted to engage or stop a projection I48 of the contact lever I8. The spring member I88 is provided witha' keyhole shaped aperture I48 so that the bushing I28 may be slipped through the larger portion of the opening and then moved laterally so that the narrower portion may engage the groove in the bushing I28 when the bushing and the spring member I88 are placed in its proper position. The switch mechanism is enclosed by a housing 26 of electrical insulating material which extends down to the bottom portion 22. Bushings 21 are provided for mounting the control upon the evaporating means 48.

As shown in Fig. 1 the switch is in the closed position. This causes current to flow to the compressor motor 48 causing, operation of the refrigerating system and the cooling of the evaporating means and the thermostat bulb 88. This reduces the pressure within the bellows 88 so that the adjusting spring H4 can gradually pull the bellows follower lever 88 downwardly. The contact lever I8 remains in its downward or closed position until the secondary lever 84 crosses the axis of the toggle spring 88. As soon as this takes place-the secondary lever 84 moves from the bottom of the slot I8 to the top of the slot 16 and the toggle spring 88 then pulls the contact lever 18 in a counter-clockwise direction until the projection I48 engages the lip I44 which serves as the normal stop for normally limiting the open movement of the lever I8. The position of the lever I8 when against the stop I44, in the open position, determines the position to which the bellows follower lever 86 must rise before it again causes the secondary lever 84 to again cross the center line of the toggle spring 66 to cause the lever I8 to again move to closed position. The amount of movement permitted the contact lever I8 determines the normal differential of the switch.

The range of the switch is controlled by the adjustment of the adjusting screw II8 which. as illustrated in Figs. 9 and 11, may be turned through the greater part of a revolution to make the switch operate at warmer or colder temperatures. As indicated in Figs. 9 and 11 the control knob I26 is provided with an off posi- 'tion. A portion of the switch is shown in the a projection I58 which in the off position engages a projection I52 of the contact lever 18. This forces the contact lever 18 to open position and holds the contact lever 18 in open position until the knob is reset. The upper portion 26 of the frame member 28 is provided with a post !54 which coacts with a projection I56 upon the control knob to prevent the control knob from being moved beyond the off position, and it also cooperates with a shoulder I58 upon the control knob for preventing the control knob from being pushed inwardly when the knob is in the off position.

Heretofore in order to provide an automatic reset single cycle defrosting mechanism it has been customary to provide a single cycle loading device which acts upon the bellows follower lever to provide an additional load thereon to raise the temperature at which the switch will close. Such a loading device ordinarily incorporates a toggle mechanism which is' moved out of the path of the bellows follower lever upon the movement of the switch to closed position upon the termination of the defrosting cycle. I find that this mechanism is somewhat complicated and difiicult to make accurately and adjust properly.

I therefore have evolved a new form of single cycle defrosting device in which I remove the normal stop for the contact lever and substitute a defrosting stop for a. single cycle to provide a wider differential for one cycle, after.. which the normal stop is automatically replaced to its normal position in which the defrosting stop does not come into use. Thus in order to provide a defrosting cycle I turn the control knob I26 to one of the warmer positions and then push it in so that, as shown in Fig. 6, the spring member I38 with its turned down lip I44 is pushed beneath the projection I46 by the downward movement of the bushing I28. The toggle springs 66 pulls .the contact lever 18 in a counter-clockwise direction considerably beyond the normal movement of the lever 18 until the post 68 which supports one end of the toggle spring 66, stops against the adjusting screw I58 provided upon a projecting ear I68 of the frame member. This adjusting screw I58 is locked in position by a. lock-nut I62.

The switch cannot then move to the on posi tion until the bellows expands sufficiently for the bellows follower lever 56 to move the sec ondary lever 64 until it crosses the center line of the toggle spring 66, after which the contact lever 18 will move to closed position. This, however, does not occur until a greater movement of the bellows follower lever 56 takes place corresponding to a much higher temperature than the normal closing temperature of the switch. This higher closing temperature causes defrosting of the evaporating means before the contact lever 18 moves to closed position. When the contact lever 18 moves to closed position, the projection I46 is moved away from the spring member I38 and permits the turned down lip I44 to return to normal position, thereby restoring the normal cycle.

In Figs. 9 to 11 there is shown a modified form of control, in which it is not necessary to turn the knob to a warmer -position before using the single cycle defrosting device. In this form the ear I68 with the stop screw I58 is omitted and in its place a stop screw I88 is provided which is threaded into a laterally projecting portion I82 of the U-shaped member I84 which corresponds to the member II6. This member I84 carries the lower end of the tension type coil spring I86 which corresponds to the coil spring H4. This coil spring I86 is anchored at its upper end to the bellows follower lever 256 which is identical to the bellows follower lever 56 of the first modification. The bellows follower lever 256 is connected to a secondary lever 264 which in turn is connected to a toggle spring 266 connected at its other end to a post 268 formed upon the contact lever 218. The contact lever 218 opens and closes the switch contacts 288 and 284 similar to the contacts 88 and 84 of the first modification.

In this form the contact lever 218 is formed with an inclined projection 3I8. When the control knob 268 is turned to the warmest position as shown in Figs. 8 and 9 the member I84 is moved downwardly carrying with it the stop screw I88. When the control knob 268 is pushed inwardly and the normal stopmember 238 corresponding to the spring member I38 is pushed downwardly, the contact lever 218 will move in a clockwise direction until the inclined projection 3I8 engages the head of the screw I88 which serves as a stop for limiting the opening movement of the contact lever 218. Thus the engagement of the inclined projection 3 I 8 with the head of the screw I88 determines the position to which the bellows follower lever 256 must move before the secondary lever 264 crosses the center line of the toggle spring to cause the contact lever 218 to move to closed position.

If the control knob is operated in the warm position it is not necessary that the effective closing temperature of the switch be raised as much above the setting of the control knob as when the control knob is in a colder position. All that it is necessary to do is to raise the closing temperature of the switch to a temperature sufiiciently above 32 F. to assure the melting of all the frost from the cooling unit. Thus a a substantially constant switch closing temperature is desired for the defrosting cycle.

The angular projection 3I8 is made at such an angle that the upward and downward movement of the head of the screw I88, which occurs with the adjustment of the control knob 268, will compensate for the change caused by the change in a tension of the main spring I86 which determines the temperature limits in normal operation. As shown in Figs. 10 and 11, when the control knob 268 is moved to its coldest position the screw I88 is moved upwardly along with the member I84 so that-it contacts the angular projection 3I8 at a higher position and thus allows the contact member 218 to open wider. This compensates for the decrease in the tension of the spring I86 caused by the upward movement of the member I84 when the control knob is moved to its coldest position. In this way substantially the same force and the same temperature is required to cause the switch to move to closed position during the defrosting cycle regardless of whether the control knob is in a warm or cold position.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A refrigerator control comprising a temperature responsive switch operating means, a snap acting switch means'operated by said temperature responsive means, a normal stop means providing a normal differential for said snap acting switch means, an abnormal stop means providing an abnormal differential for said snap acting switch means, means for temporarily rendering ineffective said normal stop means and rendering said abnormal stop means efiective, one of said first two means being eflective upon a prede- I termined movement for rendering said abnormal stop means ineffective and said normal stop means effective.

2. A refrigerator control comprising a temperature responsive switch operating means, a snap acting switch means operated by said temperature responsive means, a normal stop means providing a normal differential for said snap acting switch means, an abnormal stop means providing an abnormal differential for said snap acting switch means, means for temporarily rendering ineffective said normal stop means and rendering said abnormal stop means effective, one of said first two means being effective upon a predetermined movement for rendering said abnormal stop means ineffective and said normal stop means eifective, means for adjusting said temperature responsive switch operating means, and means controlled by said adjusting means for providing a compensating adjustment of said abnormal stop means. I

3. A refrigerator control comprising a temperature responsive switch operating means, a toggle snap acting switch means operated by said temperature responsive means, stop means for said toggle means for determining the position of the temperature responsive means required to trip the switch means, and means for temporarily changing the stop means to temporarily change the position of the temperature responsive means at which the toggle means trips and thereafter restoring the stop means to the former action.

4. A refrigerator control comprising a tem perature responsive switch operating means, a toggle snap acting switch means operated by said temperature responsive means, stop means for said toggle means for determining the position of the temperature responsive means required to trip the switch means, and means for temporarily changing the stop means to. temporarily change the position of the temperature responsive means at which the toggle means trips, said toggle means being constructed to restore the stop means to normal relationship upon tripping.

5. A refrigerator control comprising a temperature responsive switch operating means, a toggle snap acting switch means operated by said temperature responsive means, stop means for said toggle means for determining the position of the temperature responsive means required to trip the switch means, and means for temporarily changing the stop means to temporarily change the position of the temperature responsive means at which the toggle means trips and thereafter restoring the stop means to the former action, means for adjusting said temperature'responsive means, and means controlled by said adjusting means for compensating the changing of the stop means for the adjusting of the temperature responsive means.

6. A refrigerator control comprising a temperature responsive operating means, a toggle snap acting switch means operated by said temperature responsive means, stop means for limiting the opening movement of the snap actin switch means to control the position at which the temperature responsive means closes the switch means, and manually operable means for forcibly opening said snap acting switch means and for changing the stop means to change the position at which the temperature responsive means closes the switch means.

7. A refrigerator control comprising a temperature responsive operating means, a toggle snap acting switch means operated by said temperature responsive means, stop means for limiting the opening movement of the snap acting switch means to control the position at which.

the temperature responsive means closes the switch means, and manually operable means for changing thhe stop means to change the position at which the temperature responsive means closes the switch means, and means responsive to the closing of the switch means for restoring the stop means to its initial condition.

8. A refrigerator control comprising a temperature responsive operating means, a switch means operated by said temperature responsive means for opening and closing an electric circuit, a manipulating means for adjusting the temperature responsive means to change the temperatures at which the switch means is operated, means operated by said manipulating means when moved to one position for preventing the closing of the switch contacts by the temperature responsive means, and means operated by said' manipulating means when moved to another position for changing the temperature at which the temperature responsive means operates the switch contacts to provide a single abnormal cycle and thereafter resetting the control to normal cycling.

9. A refrigerator control comprising a pressure operated snap'acting switch means, means including a knob for adjusting the setting of the switch means to vary the relationship between the pressure and the operation of the switch means to open and closed position for continuous normal cycles of switch operation, means initiated by said knob for providing a single cycle having an abnormal temperature limit and thereafter returning the switch operation to the production of continuous normal cycles, and means operated by said knob for opening and preventing the reclosing of said switch means.

10. A refrigerator control comprising a pressure operated snap acting switch means, a knob, means operated by the rotary movement of said knob for adjusting the setting of the switch means to vary the relationship between the pressure and the operation of the switch means to open and closed position for continuous normal cycles of switch operation, means operated by an arial movement of said knob for providing a single cycle having an abnormal temperature limit and thereafter returning the switch operation to the production of continuous normal cycles, and means operated by said knob for opening and preventing the reclosing of said switch means.

ALBERT O. GROOMS. 

